Structure and properties of regenerated Antheraea pernyi silk fibroin in aqueous solution

Antheraea pernyi silk fibroin fibers were dissolved by aqueous lithium thiocyanate to obtain regenerated A. pernyi silk fibroin solution. By means of circular dichroism, ¹³C NMR and Raman spectroscopy, the molecular conformation of regenerated A. pernyi silk fibroin in aqueous solution was investigated. The relationship of environmental factors and sol–gel transformation behavior of regenerated A. pernyi silk fibroin was also studied. The molecular conformations of regenerated A. pernyi silk fibroin mainly were -helix and random coil in solution. There also existed a little β-sheet conformation. It was obviously different with Bombyx mori silk fibroin, whose molecular conformation in solution was only random coil but no -helix existence. With the increase of temperature and solution concentration and with the decrease of solution pH value, the gelation velocity of regenerated A. pernyi silk fibroin solution increased. Especially, it showed that A. pernyi silk fibroin was more sensitive to temperature than B. mori silk fibroin during the sol–gel transformation. The velocity increased obviously when the temperature was above 30 °C. During the sol–gel transformation, the molecular conformation of regenerated A. pernyi silk fibroin changed from random coil to β-sheet structure. The results of these studies provided important insight into the preparation of new biomaterials by silk fibroin protein.     

柞蚕卵组织蛋白酶B纯化及性质

昆虫卵内蛋白酶在胚胎发育中水解卵黄蛋白,为胚胎发育提供氨基酸,昆虫中已报道过几类卵蛋白酶,如家蚕中半胱氨酸蛋白酶和丝氨酸蛋白酶等。但是,目前尚不清楚这些蛋白酶是否存在于其他鳞翅目昆虫。了解这些蛋白酶的作用机理可以为我们提供害虫防治的新方法。并且,由于蛋白水解在许多生理过程中具有重要作用,如蛋白质的成熟和转运、受精、萌芽、肿瘤转移和其他形态发生等。因此,阐明这些蛋白酶的生物功能具有重要意义。由于（ｉ蚕卵粒大产卵量也很大,因此被选作研究鳞翅目昆虫卵蛋白酶的材料,我们希望通过对数种昆虫卵内蛋白酶的研究、找出卵黄蛋白水解的一般规律。在我们前一篇文章中报道了（ｉ蚕组织蛋白酶Ｂ的鉴定,该蛋白酶属于半胱氨酸蛋白酶类的组织蛋或最适ｐＨ为３．５,可被Ｅ－６４抑制。本文报道蛋白酶的纯化和性质。经过５步纯化过程,从（ｉ蚕卵母细胞中纯化出组织蛋白酶Ｂ,用ＳＤＳ聚丙烯酰胺凝胶电泳测得蛋白酶的亚基分子量在４７ｋＤａ左右。纯化的蛋白酶活性可被Ｅ－６４和Ｌｅｕｐｅｐｔｉｎ抑制。因此,该蛋白酶属于半胱氨酸蛋白酶。天冬氨酸蛋白酶特异性抑制剂ｐｅｐｓｔａｔｉｎ不抑制其活性。其活性可被ＤＦＰ和ＰＭＳＦ部分抑制。这两种抑制剂通常抑制丝氨酸蛋白酶活性     

AProteinase Responsible for Degrading Yolk Proteins in Tussah（Antheraea pernyi）

ＡＰｒｏｔｅｉｎａｓｅＲｅｓｐｏｎｓｉｂｌｅｆｏｒＤｅｇｒａｄｉｎｇＹｏｌｋＰｒｏｔｅｉｎｓｉｎＴｕｓｓａｈ（Ａｎｔｈｅｒａｅａｐｅｒｎｙｉ）ＺＨＡＯＸｉａｏ－ｆａｎ；（赵小凡）ＷＡＮＧＪｉｎ－ｘｉｎｇ（王金星）（ＤｅｐａｒｔｍｅｎｔｏｆＢｉｏｌｏｇ...     

A PRELIMINARY STUDY ON ISOLATION OF ECLOSION HORMONE FROM ANTHERAEA PERNYI*

Abstract Eclosion hormone (EH) was isolated from 1 500 pharate adult heads of oak silkmoth, An-theraea pernyi. The crude EH which weight 420 mg was obtained by 8 steps. The A. pernyi bioassay was adopted to test biological activity of crude EH, and total EH activity was about 750 EH units. The specific activity was approximately 560 μg/unit. The crude EH was inactivated by proteolytic enzymes. It was stable in heat and had non species-specific.     

微量添食对柞蚕蚁蚕抗逆性的影响

通过卵面微量添食葡萄糖、有益微生物 (EM)及CaCl2 3种物质 ,以半数致死时间 (LT50 )为指标 ,研究添食不同物质对柞蚕初孵蚁蚕抗逆性的影响。结果表明 ,卵面添食这 3种物质均能增强蚁蚕的抗低温能力 ,延长其在低温条件下的半数致死时间 (LT50 )。添食葡萄糖能显著延长蚁蚕对饥饿的LT50 ;添食EM能极显著延长蚁蚕对饥饿的LT50 ;添食CaCl2 对蚁蚕耐饥饿能力的影响不显著。各种添食物质对蚁蚕抗逆性的影响均存在浓度效应     

柞蚕幼虫期神经系统一氧化氮合酶的NADPH-d组织化学

运用NADPH-d组织化学整体染色方法研究柞蚕Antheraea pernyi Gu rin-Meneville幼虫神经系统中一氧化氮合酶阳性细胞的分布、数量及形态特征。结果表明,柞蚕各龄期幼虫中枢神经的脑及各神经节中都有一氧化氮合酶阳性反应,阳性神经元根据其形态大小和染色特性可分为A,B,C3种类型:A型细胞沿神经节中线分布,阳性反应较强,胞体长径约30~70μm,各神经节中的数量恒定。B型细胞多分布于神经节周边部分,阳性反应较弱,胞体长径约8~20μm,各神经节中的数量变化较大,随着龄期增加有减少的趋势。C型细胞分布于咽下神经节和第8腹神经节,在3种细胞中阳性反应最强,胞体长径约16~50μm。     

柞蚕蛹卵巢细胞的初代培养

采用MGM-448加20％胎牛血清作培养基对柞蚕蛹卵巢进行组织块培养,细胞可维持良好的生长状态达2个月之久。在此期间,细胞形态不一,且细胞聚集产生分化现象。本研究证明MGM—448培养基对柞蚕细胞原代培养来说是比较理想的培养基。     

柞蚕小热休克蛋白20.1的基因鉴定及免疫功能研究

热休克蛋白(HSP)是一类广泛存在于各类生物中的具有分子伴侣功能的蛋白质。近年来研究发现HSP与机体许多功能如免疫、凋亡、衰老等密切相关。柞蚕(Antheraea pernyi)小热休克蛋白20.1(Aphsp20.1)基因的开放读码框长度为534bp,编码178个氨基酸。序列比对结果表明,柞蚕小热休克蛋白20.1属于HSP20家族。组织定量显示这Aphsp20.1在中肠和脂肪体分布较高。此外用大肠杆菌Escherichia coli及Micrococcus luteus病原微生物注射入5龄3天柞蚕幼虫后,发现Aphsp20.1的基因表达菌明显上调。另外体外抑菌试验结果发现纯化后的蛋白也具有一定的抑菌作用。该研究表明ApHSP20.1在柞蚕的免疫功能中具有重要作用,该研究不仅为我们进一步了解更加复杂的高等生物天然免疫反应提供一些相关的研究线索;而且对柞蚕天然免疫的研究有利于更好地理解昆虫自身的免疫系统,为保护益虫防治害虫提供重要依据。